神府次烟煤在不同温度下的热溶产物表征

利用FT-IR、热重、GPC以及同步荧光分析等对神府次烟煤在不同温度条件下的1-甲基萘热溶物和热溶残煤进行了表征。结果表明,热溶物中含有较多的脂肪结构,灰分几乎全部转移至残煤中;热溶残煤与神府原煤的热失重特性存在明显差别;在300~360 ℃,随着温度升高,热溶物数均分子量呈增加趋势,进一步提高温度,分子量减小;热溶物缩合芳环数随着温度升高而增加。据此表明,在低于煤初始热解温度下神府次烟煤的热溶主要以溶剂化作用破坏煤中的非共价键为主,其中,酮、酯等轻质组分易于脱除;而高于煤初始热解温度的热溶过程则伴有侧链和桥键等弱共价键断裂的热解反应和自由基缩聚反应,热溶物中三环等稠环芳香结构增加。

Characterization of the thermal dissolution products of a subbituminous coal at different temperatures

The thermal extracts and residues of Shenfu subbituminous coal (SC) obtained from thermal dissolution in 1-methylnaphthalene (1-MN) at different temperatures were characterized by FT-IR, thermo-gravimetric (TG) analysis, GPC and synchronous fluorescence spectrometry. The results show that the thermal extracts contain more amounts of aliphatic compounds than residues. Almost all of the ash is transferred into the residue. TG analysis shows that there exists a significant difference between SC and its residues. With the thermal dissolution temperature increasing from 300 to 360 ℃, the number-average molecular weight of thermal extract increases; however, it decreases at 380 ℃. The condensed aromatic ring number of thermal extract increases with the thermal dissolution temperature rising. When the thermal dissolution of SC was carried out at temperature below initial pyrolysis temperature of SC, the thermal dissolution is dominated by the solvation of 1-MN with coal to break the non-covalent bonds in SC. The light components such as ketone and ester are easy to be released at this temperature. For thermal dissolution carried out above the initial pyrolysis temperature of SC, the pyrolysis of side chains and bridged bonds in SC and condensation reactions of free radicals take place, resulting in an increase of three-fused ring structure in thermal extract.